The Ukrainian Parliament on Tuesday passed a measure that would allow foreigners to serve in the Ukrainian Army.
But the measure will become law only with the president’s approval.
The development comes as tensions continue with Russia due to the separatist rebellion in eastern Ukraine.
Kiev and Western governments accuse Russia of sending soldiers and weapons to back the separatists, but the country denies having any direct involvement in the conflict, as it struggles economically due to Western-imposed sanctions.
Last month, Ukraine defined Russia as a “military adversary” in its official defence doctrine and signaled it was ready to join NATO, which Moscow claims is a threat to its security.
On Monday the Ukrainian military announced it has started removing tanks and light artillery from the eastern region of Luhansk as part of a deal with Russian-backed separatists that was agreed last week.
The self-proclaimed "Donetsk People's Republic," on the other hand, said its forces would begin to disarm after October 18 "on the condition that it is quiet," a rebel website reported.
Both sides have reported that violence in eastern Ukraine has ebbed to its lowest point in recent weeks.
The conflict has caused the deaths of more than 8,000 people since April 2014.